Primate Behavior and Ecology

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Primate Behavior and Ecology An animals ecology
defines the way it contacts its environment Do
particular ecologies favor certain traits over
others? Are there any generalizations we can draw
by looking across species? What are the
important variables?
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• Body size
• Ranging behavior
• Sociality
• Sex differences

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• Body size
• Body size affects
• A. metabolism

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Metabolism scales with the ¾ power of body
weight. Big animals need absolutely more food,
but less food per ounce of body size. Small
animals need absolutely less food but more food
per ounce of body size.
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Imagine provisioning A pet elephant A pet
shrew
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This is called the Kleiber Principle after the
physiologist who discovered it. It means that
large animals must eat abundant food that does
not have to be nutrient-rich. And that small
animals must eat nutrient-rich food that do not
have to be abundant.
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• Body size
• Body size affects
• A. metabolism
• B. vulnerability to predation

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Predation. Small-bodied species have more
predators that large-bodied ones. And, they may
have different anti-predator strategies. Small
hide Large active A monitor B counter-attack
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2. Ranging Behavior Home range Territory
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Day range/home range ratio
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If day range/ home range ratio is large, animals
tend to be territorial.
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If day range/ home range ratio is small, animals
can not afford to be territorial.
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3. Sociality Forage alone or with others? This
is equivalent to the question, Be solitary or
social? Costs of being social Increased
competition, for everything. Are there any
compensatory benefits?
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• Benefits of Sociality
• Anti-predator benefits
• Feeding-related benefits

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• Anti-predator benefits
• dilution
• detection
• deterrence

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• Feeding-related benefits
• finding scattered resource clumps
• defending resource clumps
• cooperative hunting

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clumped, patchy
evenly dispersed
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Be social when benefits outweigh costs. Costs
will be substantial for species that 1. Rely on
small, dispersed food items. 2. Rely on passive
(hiding) rather than active (detection and
deterrence) anti-predator strategies.
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Benefits will be substantial for species that 1.
Rely on food that occurs in large clumps that are
difficult to find but large enough to share. 2.
Rely on active (detection and deterrence)
anti-predator strategies.
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These factors are continuous (not yes-or-no). So
group size can also be predicted from balance of
costs and benefits. e.g., How big are the
patches how many animals can they be shared with
before competition outweighs food-finding
benefits?
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4. Sex differences These factors may weigh out
differently for males and females! What is the
limiting resource for each sex?
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These factors may weigh out differently for males
and females! What is the limiting resource for
each sex? females ? food
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These factors may weigh out differently for males
and females! What is the limiting resource for
each sex? females ? food males ? females
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These factors let us understand the distribution
of mating systems.